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Abstract

The purpose of this study is to investigate the efficiency of two-dimensional correlation spectroscopy (2D-COS) in recognizing the authenticity and purity of fishmeal (FM) and meat and bone meal (MBM), which are both complex mixtures with high similarity. Twenty FM samples and 20 MBM samples were obtained and examined. Temperature-dependent near-infrared (NIR) spectra were obtained using a Spectrum 400 spectrometer from 20 °C to 60 °C with an interval of 10 °C. Wavelet transform (Daubechies 5 wavelet with five levels) and baseline correction were applied to the temperature-dependent spectra in the wave range of 6000-5400 cm<sup>−1</sup>. A 2D-COS synchronous map was calculated and scaled to the range between −1 and 1. A correlation coefficient was employed to quantitatively evaluate the visual differences of synchronous maps. The results show minor differences in NIR spectral absorbency of FM and MBM, and such differences are caused by appropriate temperature perturbation and enlarged by the 2D-COS method. The sensitive wave range is found in the area of 5800-5400 cm<sup>−1</sup>. FM and MBM have observable pattern differences in the synchronous maps. Further quantitative evaluation of synchronous maps confirms correct recognizing results. Temperature-dependent 2D-COS is capable of recognizing the authenticity and purity of highly similar FM and MBM samples.